'He Lives in a Cocoon of Solipsism'

Lookups for solipsism spiked August 5th, after Washington Post columnist Charles Krauthammer used the word in reference to the Republican candidate for the presidency, Donald Trump.

He lives in a cocoon of solipsism where the world outside himself has value — indeed exists — only insofar as it sustains and inflates him. —Charles Krauthammer, The Washington Post, 4 Aug. 2016

Though 'solipsism' has a specific philosophical meaning, the word is often used to mean "extreme egocentrism."

The word may be used as a philosophical term, with the definition of “a theory holding that the self can know nothing but its own modifications and that the self is the only existent thing.” However, when the word is not being used by philosophers it typically means “extreme egocentrism”, which appears to be the sense intended by Krauthammer.

Our earliest record of the use of solipsism in English comes at the very end of the 18th century, in a translation of a work by Immanuel Kant:

If the maxims should be adopted according to those ends (which are all dictated by solipsism), the conception of duty could properly speaking have no connexion whatever with the subject in hand. —Immanuel Kant, The Metaphysic of Morals, 1799